HP SIM error Could not set the disk threshold, the agent did not accept the request ?

Hi,

I've created the scheduled task to set the disk threshold every 6 hours so that I can get alert when the disk space usage is 90% full.

But somehow when I run now with the DOMAIN\Administrator account, I get this error in some of the servers:

Could not set the disk threshold, the agent did not accept the request.

Why is that happening ?

I've confirmed that the server that is failed are all online and have the SNMP enabled, HP WBEM provider and HP Insight Management Agent installed succesfully.